U.S. patent number 7,280,319 [Application Number 11/047,400] was granted by the patent office on 2007-10-09 for suspension assembly with piezoelectric microactuators electrically connected to a folded flex circuit segment.
This patent grant is currently assigned to Western Digital Technologies, Inc.. Invention is credited to Robert J. McNab.
United States Patent |
7,280,319 |
McNab |
October 9, 2007 |
Suspension assembly with piezoelectric microactuators electrically
connected to a folded flex circuit segment
Abstract
A suspension assembly includes a load beam, a mount plate, first
and second piezoelectric microactuators, and a flex circuit
segment. The first piezoelectric microactuator is electrically
non-conductively attached to the load beam and the mount plate. The
first piezoelectric microactuator includes a first piezoelectric
element, a first top electrode, and a first bottom electrode. The
second piezoelectric microactuator is electrically non-conductively
attached to the load beam and the mount plate. The second
piezoelectric microactuator includes a second piezoelectric
element, a second top electrode, and a second bottom electrode. The
flex circuit segment is disposed folded about the first and second
piezoelectric microactuators. The flex circuit segment is in
electrical communication with the first top electrode, the first
bottom electrode, the second top electrode, and the second bottom
electrode.
Inventors: |
McNab; Robert J. (San Jose,
CA) |
Assignee: |
Western Digital Technologies,
Inc. (Lake Forest, CA)
|
Family
ID: |
38562168 |
Appl.
No.: |
11/047,400 |
Filed: |
January 31, 2005 |
Current U.S.
Class: |
360/294.4 |
Current CPC
Class: |
G11B
5/4826 (20130101); G11B 5/4853 (20130101); G11B
5/486 (20130101); G11B 5/5552 (20130101) |
Current International
Class: |
G11B
21/24 (20060101) |
Field of
Search: |
;360/294.4,265.9 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Chen; Tianjie
Attorney, Agent or Firm: Stetina, Brunda, Garred &
Brucker
Claims
I claim:
1. A suspension assembly for use with a disk drive, the suspension
assembly comprising: a load beam; a mount plate; a first
piezoelectric microactuator disposed between the load beam and the
mount plate for pivoting the load beam relative to the mount plate,
the first piezoelectric microactuator being electrically
non-conductively attached to the load beam and the mount plate for
electrically isolating the first piezoelectric microactuator from
the load beam and the mount plate, the first piezoelectric
microactuator including a first piezoelectric element, a first top
electrode disposed upon the first piezoelectric element, and a
first bottom electrode disposed upon the first piezoelectric
element opposite the first top electrode; a second piezoelectric
microactuator disposed between the load beam and the mount plate
for pivoting the load beam relative to the mount plate, the second
piezoelectric microactuator being electrically non-conductively
attached to the load beam and the mount plate for electrically
isolating the second piezoelectric microactuator from the load beam
and the mount plate, the second piezoelectric microactuator
including a second piezoelectric element, a second top electrode
disposed upon the second piezoelectric element, and a second bottom
electrode disposed upon the second piezoelectric element opposite
the second top electrode; and the first and second piezoelectric
microactuators being at least partially enclosed by a folded flex
circuit segment, the flex circuit segment being in electrical
communication with the first top electrode, the first bottom
electrode, the second top electrode, and the second bottom
electrode.
2. The suspension assembly of claim 1 wherein the first and second
piezoelectric microactuators are electrically non-conductively
attached to the load beam and the mount plate with non-conductive
adhesive.
3. The suspension assembly of claim 1 wherein the first and second
piezoelectric elements each have opposing first and second ends,
the first ends are each respectively electrically non-conductively
attached to the load beam, the second ends are each respectively
electrically non-conductively attached to the mount plate.
4. The suspension assembly of claim 3 wherein the first ends are
each respectively electrically non-conductively attached to the
load beam with non-conductive adhesive, the second ends are each
respectively electrically non-conductively attached to the mount
plate with non-conductive adhesive.
5. The suspension assembly of claim 1 wherein the first and second
bottom electrodes are disposed between the load beam and the mount
plate without being in electrical contact with the load beam and
the mount plate.
6. The suspension assembly of claim 1 further includes a flex
circuit assembly with a head trace segment disposed along the load
beam.
7. The suspension assembly of claim 6 wherein the flex circuit
segment is integrally formed with the flex circuit assembly.
8. The suspension assembly of claim 1 wherein the flex circuit
segment includes first, second, and third traces electrically
connected to the first and second piezoelectric microactuators.
9. The suspension assembly of claim 8 wherein the first trace is
electrically connected to the first top electrode, the second trace
is electrically connected to the second top electrode and the first
bottom electrode, the third trace is electrically connected to the
second bottom electrode.
10. A head stack assembly for use with a disk drive, the head stack
assembly comprising: an actuator arm; and a suspension assembly
attached to the actuator arm, the suspension assembly including: a
load beam; a mount plate coupled to the actuator arm; a first
piezoelectric microactuator disposed between the load beam and the
mount plate for pivoting the load beam relative to the mount plate,
the first piezoelectric microactuator being electrically
non-conductively attached to the load beam and the mount plate for
electrically isolating the first piezoelectric microactuator from
the load beam and the mount plate, the first piezoelectric
microactuator including a first piezoelectric element, a first top
electrode disposed upon the first piezoelectric element, and a
first bottom electrode disposed upon the first piezoelectric
element opposite the first top electrode; a second piezoelectric
microactuator disposed between the load beam and the mount plate
for pivoting the load beam relative to the mount plate, the second
piezoelectric microactuator being electrically non-conductively
attached to the load beam and the mount plate for electrically
isolating the second piezoelectric microactuator from the load beam
and the mount plate, the second piezoelectric microactuator
including a second piezoelectric element, a second top electrode
disposed upon the second piezoelectric element, and a second bottom
electrode disposed upon the second piezoelectric element opposite
the second top electrode; and the first and second piezoelectric
microactuators being at least partially enclosed by a folded flex
circuit segment, the flex circuit segment being in electrical
communication with the first top electrode, the first bottom
electrode, the second top electrode, and the second bottom
electrode.
11. The head stack assembly of claim 10 wherein the first and
second piezoelectric microactuators are electrically
non-conductively attached to the load beam and the mount plate with
non-conductive adhesive.
12. The head stack assembly of claim 10 wherein the first and
second piezoelectric elements each have opposing first and second
ends, the first ends are each respectively electrically
non-conductively attached to the load beam, the second ends are
each respectively electrically non-conductively attached to the
mount plate.
13. The head stack assembly of claim 12 wherein the first ends are
each respectively electrically non-conductively attached to the
load beam with non-conductive adhesive, the second ends are each
respectively electrically non-conductively attached to the mount
plate with non-conductive adhesive.
14. The head stack assembly of claim 10 wherein the first and
second bottom electrodes are disposed between the load beam and the
mount plate without being in electrical contact with the load beam
and the mount plate.
15. The head stack assembly of claim 10 further includes a slider
supported by the load beam and a flex circuit assembly with a head
trace segment disposed along the load beam in electrical
communication with the slider.
16. The head stack assembly of claim 15 wherein the flex circuit
segment is integrally formed with the flex circuit assembly.
17. The head stack assembly of claim 10 wherein the flex circuit
segment includes first, second, and third traces electrically
connected to the first and second piezoelectric microactuators.
18. The head stack assembly of claim 17 wherein the first trace is
electrically connected to the first top electrode, the second trace
is electrically connected to the second top electrode and the first
bottom electrode, the third trace is electrically connected to the
second bottom electrode.
19. A disk drive comprising: a disk drive base; and a head stack
assembly rotatably coupled to the disk drive base, the head stack
assembly including an actuator arm and a suspension assembly
attached to the actuator arm, the suspension assembly including: a
load beam; a mount plate coupled to the actuator arm; a first
piezoelectric microactuator disposed between the load beam and the
mount plate for pivoting the load beam relative to the mount plate,
the first piezoelectric microactuator being electrically
non-conductively attached to the load beam and the mount plate for
electrically isolating the first piezoelectric microactuator from
the load beam and the mount plate, the first piezoelectric
microactuator including a first piezoelectric element, a first top
electrode disposed upon the first piezoelectric element, and a
first bottom electrode disposed upon the first piezoelectric
element opposite the first top electrode; a second piezoelectric
microactuator disposed between the load beam and the mount plate
for pivoting the load beam relative to the mount plate, the second
piezoelectric microactuator being electrically non-conductively
attached to the load beam and the mount plate for electrically
isolating the second piezoelectric microactuator from the load beam
and the mount plate, the second piezoelectric microactuator
including a second piezoelectric element, a second top electrode
disposed upon the second piezoelectric element, and a second bottom
electrode disposed upon the second piezoelectric element opposite
the second top electrode; and the first and second piezoelectric
microactuators being at least partially enclosed by a folded flex
circuit segment, the flex circuit segment being in electrical
communication with the first top electrode, the first bottom
electrode, the second top electrode, and the second bottom
electrode.
20. The disk drive of claim 19 wherein the first and second
piezoelectric microactuators are electrically non-conductively
attached to the load beam and the mount plate with non-conductive
adhesive.
21. The disk drive of claim 19 wherein the first and second
piezoelectric elements each have opposing first and second ends,
the first ends are each respectively electrically non-conductively
attached to the load beam, the second ends are each respectively
electrically non-conductively attached to the mount plate.
22. The disk drive of claim 21 wherein the first ends are each
respectively electrically non-conductively attached to the load
beam with non-conductive adhesive, the second ends are each
respectively electrically non-conductively attached to the mount
plate with non-conductive adhesive.
23. The disk drive of claim 19 wherein the first and second bottom
electrodes are disposed between the load beam and the mount plate
without being in electrical contact with the load beam and the
mount plate.
24. The disk drive of claim 19 wherein the head stack assembly
further includes a slider supported by the load beam, the head
stack assembly further includes a flex circuit assembly with a head
trace segment disposed along the load beam in electrical
communication with the slider.
25. The disk drive of claim 24 wherein the flex circuit segment is
integrally formed with the flex circuit assembly.
26. The disk drive of claim 19 wherein the flex circuit segment
includes first, second, and third traces electrically connected to
the first and second piezoelectric microactuators.
27. The disk drive of claim 26 wherein the first trace is
electrically connected to the first top electrode, the second trace
is electrically connected to the second top electrode and the first
bottom electrode, the third trace is electrically connected to the
second bottom electrode.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to disk drives, and in
particular to a disk drive suspension assembly with piezoelectric
microactuators electrically connected to a folded flex circuit
segment.
2. Description of the Prior Art
The typical hard disk drive includes a head disk assembly (HDA) and
a printed circuit board assembly (PCBA) attached to a disk drive
base of the HDA. The head disk assembly includes at least one
magnetic disk, a spindle motor for rotating the disk, and a head
stack assembly (HSA). The spindle motor includes a spindle motor
hub that is rotatably attached to the disk drive base. The hub has
an outer hub flange that supports a lowermost one of the disks.
Additional disks may be stacked and separated with annular disk
spacers that are disposed about the hub.
The head stack assembly has an actuator assembly having at least
one transducer head (typically a magneto-resistive or "MR" head),
typically several, for reading and writing data from and to the
disk. The printed circuit board assembly includes a servo control
system in the form of a disk controller for generating servo
control signals. The head stack assembly is controllably positioned
in response to the generated servo control signals from the disk
controller. In so doing, the attached heads are moved relative to
tracks disposed upon the disk.
In further detail, the head stack assembly includes an actuator
assembly, at least one head gimbal assembly, and a flex circuit
cable assembly. A conventional "rotary" or "swing-type" actuator
assembly typically includes an actuator having an actuator body.
The actuator body is configured to rotate on a pivot assembly
between limited positions about an axis of rotation. A coil support
extends from one side of the actuator body. A coil is supported by
the coil support and is configured to interact with one or more
permanent magnets to form a voice coil motor. One or more actuator
arms extend from an opposite side of the actuator body. To
facilitate rotational movement of the actuator, the actuator
assembly further includes the actuator body that has a bore and a
pivot bearing cartridge engaged within the bore. Each magnetic disk
includes opposing disk surfaces. Data may be recorded on a single
surface or both along data annular regions. As such, the head stack
assembly may be pivoted such that each transducer head is disposed
adjacent the various data annular regions from adjacent the outer
diameter to the inner diameter of each disk.
Conductive traces (formed of copper for example) are laid on a
dielectric layer (such as a polyimide film) formed on the head
gimbal assembly. The dielectric layer electrically insulates the
conductive traces from the gimbal (which may be formed of stainless
steel for example). Such technologies are variously named TSA
(Trace Suspension Assembly), NSL (No Service Loop), FOS (Flex On
Suspension) and the like. These conductive traces interconnect the
elements of the transducer head to drive a preamp and the circuits
associated therewith.
A typical suspension assembly includes a load beam (also referred
to as a "suspension") and a mount plate (also referred to as a
"base plate," a "nut plate" or a "swage plate"). The mount plate is
used to attach the load beam to the end of the actuator arms,
typically through a swage engagement. The suspension assembly
further includes the gimbal supported at the end of the load beam.
A hinge plate may also be utilized which is interposed between the
load beam and the mount plate. The suspension assembly with the
slider attached to the gimbal is typically referred to as a head
gimbal assembly.
The transducer head is disposed within the slider. The load beam
has a spring function that provides a "gram load" biasing force and
a hinge function that permits the head to follow the surface
contour of the spinning disk. The load beam has an actuator end
that connects to the actuator arm and a gimbal end that connects to
the gimbal that carries the slider and transmits the gram load
biasing force to the slider to "load" the slider against the disk.
A rapidly spinning disk develops a laminar airflow above its
surface that lifts the slider including the head away from the disk
in opposition to the gram load biasing force. The slider is said to
be "flying" over the disk when in this state.
As disk drives have progressed to higher areal densities, the fly
height and the fly height tolerances has been correspondingly
reduced. As such, the ability to maintain the slider within such
operational specifications has become increasingly difficult.
Accordingly, there is a need in the art for a disk drive having an
improved suspension assembly design in comparison to the prior
art.
SUMMARY OF THE INVENTION
An aspect of the present invention can be regarded as a suspension
assembly for use with a disk drive. The suspension assembly
includes a load beam, a mount plate, first and second piezoelectric
microactuators, and a flex circuit segment. The first piezoelectric
microactuator is disposed between the load beam and the mount plate
for pivoting the load beam relative to the mount plate. The first
piezoelectric microactuator is electrically non-conductively
attached to the load beam and the mount plate for electrically
isolating the first piezoelectric microactuator from the load beam
and the mount plate. The first piezoelectric microactuator includes
a first piezoelectric element, a first top electrode disposed upon
the first piezoelectric element, and a first bottom electrode
disposed upon the first piezoelectric element opposite the first
top electrode. The second piezoelectric microactuator is disposed
between the load beam and the mount plate for pivoting the load
beam relative to the mount plate. The second piezoelectric
microactuator is electrically non-conductively attached to the load
beam and the mount plate for electrically isolating the second
piezoelectric microactuator from the load beam and the mount plate.
The second piezoelectric microactuator includes a second
piezoelectric element, a second top electrode disposed upon the
second piezoelectric element, and a second bottom electrode
disposed upon the second piezoelectric element opposite the second
top electrode. The flex circuit segment is disposed folded about
the first and second piezoelectric microactuators. The flex circuit
segment is in electrical communication with the first top
electrode, the first bottom electrode, the second top electrode,
and the second bottom electrode.
According to various embodiments, the first and second
piezoelectric microactuators may be electrically non-conductively
attached to the load beam and the mount plate with non-conductive
adhesive. The first and second piezoelectric elements may each have
opposing first and second ends. The first ends may each be
respectively electrically non-conductively attached to the load
beam, and the second ends may each be respectively electrically
non-conductively attached to the mount plate. The first ends may
each be respectively electrically non-conductively attached to the
load beam with non-conductive adhesive, and the second ends may
each be respectively electrically non-conductively attached to the
mount plate with non-conductive adhesive. The first and second
bottom electrodes may be disposed between the load beam and the
mount plate without being in electrical contact with the load beam
and the mount plate. The suspension assembly may further include a
flex circuit assembly with a head trace segment disposed along the
load beam. The flex circuit segment may be integrally formed with
the flex circuit assembly. The flex circuit segment may include a
first, second and third traces electrically connected to the first
and second piezoelectric microactuators. The first trace may be
electrically connected to the first top electrode, the second trace
may be electrically connected to the second top electrode and the
first bottom electrode, and the third trace may be electrically
connected to the second bottom electrode.
According to another aspect of the present invention, there is
provided a head stack assembly for use with a disk drive. The head
stack assembly includes an actuator arm and a suspension assembly
attached to the actuator arm. The suspension assembly is as
described above. According to another aspect of the present
invention, there is provided a disk drive. The disk drive includes
a disk drive base and a head stack assembly rotatably coupled to
the disk drive base. The head stack assembly is as described
above.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a disk drive in
accordance with the present invention;
FIG. 2 is an enlarged top perspective view of a suspension assembly
of the disk drive of FIG. 1 including a flex circuit segment and
piezoelectric micro actuators in accordance with an aspect of the
present invention;
FIG. 3 is the enlarged top perspective view of the suspension
assembly of FIG. 2 as shown with the flex circuit segment in an
unfolded position;
FIG. 4 is the enlarged top perspective view of the suspension
assembly of FIG. 2 as shown without the flex circuit segment;
FIG. 5 is an enlarged top perspective view of the suspension
assembly of FIG. 2 as seen from another viewing angle;
FIG. 6 is a bottom plan view of the suspension assembly of FIG. 3;
and
FIG. 7 is the bottom plan view of the suspension assembly of FIG.
6, however, as shown without the piezoelectric microactuators.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings wherein the showings are for purposes
of illustrating preferred embodiments of the present invention
only, and not for purposes of limiting the same, FIGS. 1-7
illustrate a disk drive and a suspension assembly in accordance
with the aspects of the present invention.
Referring now to FIG. 1, there is depicted an exploded perspective
view of a disk drive 10 as constructed in accordance with an aspect
of the present invention. The disk drive 10 includes a head disk
assembly (HDA) 12 and a printed circuit board assembly (PCBA) 14.
The head disk assembly 12 includes a disk drive housing with a disk
drive base 16 and a cover 18.
Referring now to FIG. 1 there is depicted an exploded perspective
view of a disk drive 10 constructed in accordance with an aspect of
the present invention. In the embodiment shown, the disk drive 10
includes a head disk assembly (HDA) 12 and a printed circuit board
assembly (PCBA) 14. The head disk assembly 12 includes a housing
which may include a disk drive base 16 and a cover 18 that
collectively house magnetic disks 20, 22. Each magnetic disk 20, 22
contains a plurality of tracks for storing data.
The head disk assembly 12 further includes a spindle motor 24 for
rotating the disks 20, 22 about an axis of rotation 26. The head
disk assembly 12 further includes a head stack assembly 28
rotatably attached to the disk drive base 16 in operable
communication with the disks 20, 22. The head stack assembly 28
includes a rotary actuator 30. In the embodiment shown, the
actuator 30 includes an actuator body 32 and actuator arms (the
uppermost one denoted 34) that extend from the actuator body 32.
Distally attached to each of the actuator arms 34 is a suspension
assembly (the uppermost one denoted 36). Each suspension assembly
36 respectively supports a slider (the uppermost one denoted 38).
Each of the sliders 38 includes a transducer head. The suspension
assemblies 36 with the sliders 38 are referred to as head gimbal
assemblies. It is contemplated that the number of actuator arms and
suspension assemblies may vary depending upon the number of disks
and disk surfaces utilized.
The actuator body 32 includes a bore, and the actuator 30 further
includes a pivot bearing cartridge engaged within the bore for
facilitating the actuator body 32 to rotate between limited
positions about an actuator axis of rotation 40. The actuator 30
further includes a coil support 42 that extends from one side of
the actuator body 32 opposite the actuator arms 40. In this
embodiment, the coil support 42 is configured to support a coil 44.
A pair of magnetic elements 46, 48 is supported by mounts 50, 52
which are attached to the disk drive base 16 (magnetic element 46
is indicated by the dashed lead line and it is understood that the
magnetic element 46 is disposed underneath the mount 50). The coil
44 interacts with the magnetic elements 46, 48 to form a voice coil
motor for controllably rotating the actuator 30.
The head stack assembly 28 further includes a flex circuit assembly
54 and a cable connector 56. The cable connector 56 is attached to
the disk drive base 16 and is disposed in electrical communication
with the printed circuit board 14. The flex circuit assembly 54
supplies current to the actuator coil 44 and carries signals
between the transducer heads of the sliders 38 and the printed
circuit board assembly 14.
Referring now to FIG. 2, there is depicted an enlarged top
perspective view of the suspension assembly 36 of the disk drive 10
of FIG. 1. Also shown is a portion the flex circuit assembly 54.
The flex circuit assembly 54 includes electrical traces 58 for
connection with the slider 38. As is discussed in detail below, the
suspension assembly 36 of the present invention includes a flex
circuit segment 60 and first and second piezoelectric
microactuators 62, 64 in accordance with an aspect of the present
invention. FIG. 3 is the enlarged top perspective view of the
suspension assembly 36 of FIG. 2 as shown with the flex circuit
segment 60 in an unfolded position. For ease of viewing the first
and second piezoelectric microactuators 62, 64, FIG. 4 is the
enlarged top perspective view of the suspension assembly 36 of FIG.
2 as shown without the flex circuit segment 60. FIG. 5 is an
enlarged top perspective view of the suspension assembly 36 of FIG.
2 as seen from another viewing angle. FIG. 6 is a bottom plan view
of the suspension assembly 36 of FIG. 3. Finally, for ease of
viewing the flex circuit segment 60, FIG. 7 is the bottom plan view
of the suspension assembly 36 of FIG. 6, however, as shown without
the first and second piezoelectric microactuators 62, 64.
The suspension assembly 36 includes a mount plate 66. The mount
plate 66 is used to attach the suspension assembly 36 to the
actuator arm 34. The mount plate 66 may include a swage opening 68
that is utilized to attach the mount plate 66 to the actuator arm
34 via a swaging operation.
The suspension assembly includes a load beam 70. The slider 38 is
coupled to the load beam 70. The mount plate 66 defines a
longitudinal axis 72. As discussed below, the first and second
piezoelectric microactuators 62, 64 are selectively actuated to
pivot the load beam and therefore the slider 38 with respect to the
longitudinal axis 72 as indicated be the arced lined arrows. As
such, the first and second piezoelectric microactuators 62, 64 are
utilized to move the slider 38 relative to the actuator arm 34 for
secondary controlled positioning of the slider 38 with respect to
tracks disposed upon the disk 20.
An aspect of the present invention can be regarded as a suspension
assembly 36 for use with the disk drive 10. The suspension assembly
36 includes the load beam 70, the mount plate 66, the first and
second piezoelectric microactuators 62, 64, and the flex circuit
segment 60.
The first piezoelectric microactuator 62 is disposed between the
load beam 70 and the mount plate 66 for pivoting the load beam 70
relative to the mount plate 66. The first piezoelectric
microactuator 62 is electrically non-conductively attached to the
load beam 70 and the mount plate 66 for electrically isolating the
first piezoelectric microactuator 62 from the load beam 70 and the
mount plate 66. The first piezoelectric microactuator 62 includes a
first piezoelectric element 74, a first top electrode 76 disposed
upon the first piezoelectric element 74, and a first bottom
electrode 78 disposed upon the first piezoelectric element 74
opposite the first top electrode 76.
The second piezoelectric microactuator 64 is disposed between the
load beam 70 and the mount plate 66 for pivoting the load beam 70
relative to the mount plate 66. The second piezoelectric
microactuator 64 is electrically non-conductively attached to the
load beam 70 and the mount plate 66 for electrically isolating the
second piezoelectric microactuator 64 from the load beam 70 and the
mount plate 66. The second piezoelectric microactuator 64 includes
a second piezoelectric element 80, a second top electrode 82
disposed upon the second piezoelectric element 80, and a second
bottom electrode 84 disposed upon the second piezoelectric element
80 opposite the second top electrode 82.
The flex circuit segment 60 is disposed folded about the first and
second piezoelectric microactuators 62, 64 as shown in the
embodiment of FIG. 2. The flex circuit segment 60 is in electrical
communication with the first top electrode 76, the first bottom
electrode 78, the second top electrode 82, and the second bottom
electrode 84.
In further detail, the first and second piezoelectric
microactuators 62, 64 are formed to deform in response to changes
in electrical input respectively across the first and second
piezoelectric elements 74, 80. In the particular embodiment shown,
the first and second piezoelectric microactuators 62, 64 take the
form of elongate rectangular structures that are generally aligned
with the longitudinal axis 72. The first and second piezoelectric
microactuators 62, 64 are configured to longitudinally expand
and/or contract in response to changes in electrical input
respectively across the first and second piezoelectric elements 74,
80. It is contemplated that the first and second piezoelectric
microactuators 62, 64 may be constructed according to those
techniques which are well known to one of ordinary skill in the
art.
According to various embodiments, the first and second
piezoelectric microactuators 62, 64 may be electrically
non-conductively attached to the load beam 70 and the mount plate
66 with non-conductive adhesive. The first and second piezoelectric
elements 74, 80 may each have opposing first and second ends 86,
88. The first ends 86 may each be respectively electrically
non-conductively attached to the load beam 70, and the second ends
88 may each be respectively electrically non-conductively attached
to the mount plate 66. The first ends 86 may each be respectively
electrically non-conductively attached to the load beam 70 with
non-conductive adhesive, and the second ends 88 may each be
respectively electrically non-conductively attached to the mount
plate 66 with non-conductive adhesive. Though not shown, it is
contemplated that the first and second bottom electrodes 78, 84 may
each be respectively electrically non-conductively attached to the
mount plate 66 with non-conductive adhesive.
In the embodiment shown, the first and second bottom electrodes 78,
84 are disposed between the load beam 70 and the mount plate 66
without being in electrical contact with the load beam 70 and the
mount plate 66. In this regard, the first and second bottom
electrodes may be formed to extend only along a central portion of
the first and second piezoelectric elements 74, 80. The first and
second bottom electrodes 78, 84 may be formed using a deposition
technique that involves masking the first and second ends 86, 88 of
the first and second piezoelectric elements 74, 80.
The flex circuit assembly 54 may include a head trace segment 90
disposed along the load beam 70. The head trace segment 90 is
disposed in electrical communication with the slider 38. It is
contemplated that the flex circuit assembly 54 may include a trace
suspension assembly backing layer with a gimbal configured to
support the slider 38. The traces 58 (which may be formed of copper
for example) are laid on a dielectric layer (such as a polyimide
film). The dielectric layer may be formed on the trace suspension
assembly backing layer. The dielectric layer electrically insulates
the traces 58.
The flex circuit segment 60 may be integrally formed with the flex
circuit assembly 54 as shown. However, it is contemplated that the
flex circuit segment 60 may be separately formed from the flex
circuit assembly 54 and subsequently electrically connected
thereto.
The flex circuit segment 60 may include first, second and third
traces 100, 102, 104 electrically connected to the first and second
piezoelectric microactuators 62, 64. The first trace 100 may be
electrically connected to the first top electrode 76, the second
trace 102 may be electrically connected to the second top electrode
82 and the first bottom electrode 78, and the third trace 104 may
be electrically connected to the second bottom electrode 84.
As such, it is recognized that only three traces need be utilized
to service the four electrodes with a common trace between the
first and second piezoelectric microactuators 62, 64. This is
because the first and second piezoelectric elements 74, 80 are
actuated by changes in the electrical input across the element 74,
80 (e.g., change in voltage potential). It is further recognized
that even just two traces could be used to service the four
electrodes. In addition, there may be a one to one correspondence
of the traces to the electrodes.
The flex circuit segment 60 may include pads 92, 94, 96, 98 which
are used to respectively electrically connect to the first top
electrode 76, the second top electrode 82, the second bottom
electrode 84, and the first bottom electrode 78. Trace 100 is
electrically connected to pad 92. Trace 102 is electrically
connected to pads 94, 98. Trace 104 is electrically connected to
pad 96.
It is contemplated that the folded configuration of the flex
circuit segment 60 facilitates an efficient method of electrically
connecting to the first and second piezoelectric microactuators 62,
64. In this regard, the disposition of the electrodes 76, 78, 82,
84 upon the respective opposing planar surfaces of the first and
second piezoelectric elements 74, 80 facilitates the readily
accessible nature of the electrodes 76, 78, 82, 84 by the flex
circuit segment 60 in the folded configuration. Moreover, the
folded configuration of the flex circuit segment 60 allows use of a
single piece of flex circuit material to facilitate such electrical
connections.
According to another aspect of the present invention, there is
provided the head stack assembly 28 for use with the disk drive 10.
The head stack assembly 28 includes the actuator arm 34 and the
suspension assembly 36 attached to the actuator arm 34. The
suspension assembly 36 is as described above. According to yet
another aspect of the present invention, there is provided the disk
drive 10. The disk drive 10 includes the disk drive base 16 and the
head stack assembly 28 rotatably coupled to the disk drive base 16.
The head stack assembly 28 is as described above.
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